...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Powder Technology: An International Journal on the Science and Technology of Wet and Dry Particulate Systems >New characterization methods for powder die fill process for producing powder metallurgical components
【24h】

New characterization methods for powder die fill process for producing powder metallurgical components

机译：粉末冶金零件生产粉末冶金零件的新表征方法

获取原文
获取原文并翻译 | 示例
   

获取外文期刊封面封底 >>

       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Powder die fill (PDF) process prior to compaction affects spatial density of the final part and its in-service performance. Inhomogeneous density leads to part distortion (or warpage) during sintering, resulting in inability to get the desired dimensional tolerances and mechanical properties in the final product. Therefore, to improve quality of the final part, it is important to eliminate several causes of non-uniformity during the powder die filling stage. This experimental study relates to some new approaches toward characterization of PDF process, using an experimental apparatus with transparent shoe and die sections. In this paper, the influence of a newly designed perforated plate (PP), incorporated at the bottom of the feed shoe on PDF is studied. The effect of PP on powder redistribution in the feed shoe, powder transfer and resulting powder spatial density uniformity, and porosity within a thin ring-shaped die is compared with the powder flow and segregation behavior in standard shoe (SS) filling. Various colored salt powder experiments using arrangements in layers and columns within the feed shoe as well as a commercial iron power are considered in an attempt to analyze the subsequent powder redistribution within the shoe, during shoe motion and final powder packing in the die. It is determined that the colored salt is a promising medium for simulating the flow characteristics and segregation of commercial iron powder macroscopically. Further, critical shoe speed for powder delivery into the die-cavity using a perforated plate and a standard shoe are studied. Continuous imaging of the transparent shoe and die wall sections with an on-line high speed CCD camera are also used to record powder flow and to obtain resulting porosity from quantitative pixel-based analysis of the post-fill final images. The effectiveness and limitations of the perforated plate in achieving a more homogenous powder fill and reduced porosity in the die is explained with the help of both colored powder experiments and the surface porosity data from the transparent die face section. Finally, a successful attempt is made to bind the loose iron powder using a polymer resin blend into the shape of a ring within the die. This ring shaped component is then analyzed for its spatial porosity distribution, and thereby its spatial density distribution, using gamma ray densitometry.
机译：压实之前的粉末压模填充（PDF）工艺会影响最终零件的空间密度及其使用性能。密度不均匀会导致烧结过程中零件变形（或翘曲），导致无法在最终产品中获得所需的尺寸公差和机械性能。因此，为了提高最终零件的质量，重要的是消除在粉末压模填充阶段不均匀的几种原因。这项实验研究涉及使用具有透明靴和模头部分的实验设备来表征PDF过程的一些新方法。在本文中，研究了装在进料靴底部的新型设计的穿孔板（PP）对PDF的影响。将PP对进料靴中粉末的重新分布，粉末转移以及所产生的粉末空间密度均匀性和薄环形模具内的孔隙率的影响与标准靴（SS）填充中的粉末流动和偏析行为进行了比较。考虑使用进料靴内的层和列中的布置以及商用铁粉进行的各种有色盐粉实验，以尝试分析在靴运动和模具中最终粉末填充期间，随后在靴内的粉末重新分布。已确定，有色盐是从宏观上模拟商品铁粉的流动特性和偏析的有前途的介质。此外，还研究了使用穿孔板和标准滑块将粉末输送到模腔中的临界滑块速度。还使用在线高速CCD相机对透明的鞋和模具壁部分进行连续成像，以记录粉末流动并从基于填充后最终图像的基于像素的定量分析获得最终的孔隙率。借助于有色粉末实验和来自透明模具表面部分的表面孔隙率数据，说明了多孔板在实现更均匀的粉末填充和降低模具中孔隙率方面的有效性和局限性。最终，成功尝试使用聚合物树脂共混物将松散的铁粉粘合成模具内的环形。然后使用伽马射线密度法分析该环形部件的空间孔隙率分布，进而分析其空间密度分布。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号